/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

#include "cbtManifoldResult.h"
#include "BulletCollision/NarrowPhaseCollision/cbtPersistentManifold.h"
#include "BulletCollision/CollisionDispatch/cbtCollisionObject.h"
#include "BulletCollision/CollisionDispatch/cbtCollisionObjectWrapper.h"

///This is to allow MaterialCombiner/Custom Friction/Restitution values
ContactAddedCallback gContactAddedCallback = 0;

CalculateCombinedCallback gCalculateCombinedRestitutionCallback = &cbtManifoldResult::calculateCombinedRestitution;
CalculateCombinedCallback gCalculateCombinedFrictionCallback = &cbtManifoldResult::calculateCombinedFriction;
CalculateCombinedCallback gCalculateCombinedRollingFrictionCallback = &cbtManifoldResult::calculateCombinedRollingFriction;
CalculateCombinedCallback gCalculateCombinedSpinningFrictionCallback = &cbtManifoldResult::calculateCombinedSpinningFriction;
CalculateCombinedCallback gCalculateCombinedContactDampingCallback = &cbtManifoldResult::calculateCombinedContactDamping;
CalculateCombinedCallback gCalculateCombinedContactStiffnessCallback = &cbtManifoldResult::calculateCombinedContactStiffness;

cbtScalar cbtManifoldResult::calculateCombinedRollingFriction(const cbtCollisionObject* body0, const cbtCollisionObject* body1)
{
	cbtScalar friction = body0->getRollingFriction() * body1->getFriction() + body1->getRollingFriction() * body0->getFriction();

	const cbtScalar MAX_FRICTION = cbtScalar(10.);
	if (friction < -MAX_FRICTION)
		friction = -MAX_FRICTION;
	if (friction > MAX_FRICTION)
		friction = MAX_FRICTION;
	return friction;
}

cbtScalar cbtManifoldResult::calculateCombinedSpinningFriction(const cbtCollisionObject* body0, const cbtCollisionObject* body1)
{
	cbtScalar friction = body0->getSpinningFriction() * body1->getFriction() + body1->getSpinningFriction() * body0->getFriction();

	const cbtScalar MAX_FRICTION = cbtScalar(10.);
	if (friction < -MAX_FRICTION)
		friction = -MAX_FRICTION;
	if (friction > MAX_FRICTION)
		friction = MAX_FRICTION;
	return friction;
}

///User can override this material combiner by implementing gContactAddedCallback and setting body0->m_collisionFlags |= cbtCollisionObject::customMaterialCallback;
cbtScalar cbtManifoldResult::calculateCombinedFriction(const cbtCollisionObject* body0, const cbtCollisionObject* body1)
{
	cbtScalar friction = body0->getFriction() * body1->getFriction();

	const cbtScalar MAX_FRICTION = cbtScalar(10.);
	if (friction < -MAX_FRICTION)
		friction = -MAX_FRICTION;
	if (friction > MAX_FRICTION)
		friction = MAX_FRICTION;
	return friction;
}

cbtScalar cbtManifoldResult::calculateCombinedRestitution(const cbtCollisionObject* body0, const cbtCollisionObject* body1)
{
	return body0->getRestitution() * body1->getRestitution();
}

cbtScalar cbtManifoldResult::calculateCombinedContactDamping(const cbtCollisionObject* body0, const cbtCollisionObject* body1)
{
	return body0->getContactDamping() + body1->getContactDamping();
}

cbtScalar cbtManifoldResult::calculateCombinedContactStiffness(const cbtCollisionObject* body0, const cbtCollisionObject* body1)
{
	cbtScalar s0 = body0->getContactStiffness();
	cbtScalar s1 = body1->getContactStiffness();

	cbtScalar tmp0 = cbtScalar(1) / s0;
	cbtScalar tmp1 = cbtScalar(1) / s1;
	cbtScalar combinedStiffness = cbtScalar(1) / (tmp0 + tmp1);
	return combinedStiffness;
}

cbtManifoldResult::cbtManifoldResult(const cbtCollisionObjectWrapper* body0Wrap, const cbtCollisionObjectWrapper* body1Wrap)
	: m_manifoldPtr(0),
	  m_body0Wrap(body0Wrap),
	  m_body1Wrap(body1Wrap)
#ifdef DEBUG_PART_INDEX
	  ,
	  m_partId0(-1),
	  m_partId1(-1),
	  m_index0(-1),
	  m_index1(-1)
#endif  //DEBUG_PART_INDEX
	  ,
	  m_closestPointDistanceThreshold(0)
{
}

void cbtManifoldResult::addContactPoint(const cbtVector3& normalOnBInWorld, const cbtVector3& pointInWorld, cbtScalar depth)
{
	cbtAssert(m_manifoldPtr);
	//order in manifold needs to match

	if (depth > m_manifoldPtr->getContactBreakingThreshold()) {
		//	if (depth > m_manifoldPtr->getContactProcessingThreshold())
		return;
	}
	bool isSwapped = m_manifoldPtr->getBody0() != m_body0Wrap->getCollisionObject();
	bool isNewCollision = m_manifoldPtr->getNumContacts() == 0;

	cbtVector3 pointA = pointInWorld + normalOnBInWorld * depth;

	cbtVector3 localA;
	cbtVector3 localB;

	if (isSwapped)
	{
		localA = m_body1Wrap->getCollisionObject()->getWorldTransform().invXform(pointA);
		localB = m_body0Wrap->getCollisionObject()->getWorldTransform().invXform(pointInWorld);
	}
	else
	{
		localA = m_body0Wrap->getCollisionObject()->getWorldTransform().invXform(pointA);
		localB = m_body1Wrap->getCollisionObject()->getWorldTransform().invXform(pointInWorld);
	}

	cbtManifoldPoint newPt(localA, localB, normalOnBInWorld, depth);
	newPt.m_positionWorldOnA = pointA;
	newPt.m_positionWorldOnB = pointInWorld;

	int insertIndex = m_manifoldPtr->getCacheEntry(newPt);

	newPt.m_combinedFriction = gCalculateCombinedFrictionCallback(m_body0Wrap->getCollisionObject(), m_body1Wrap->getCollisionObject());
	newPt.m_combinedRestitution = gCalculateCombinedRestitutionCallback(m_body0Wrap->getCollisionObject(), m_body1Wrap->getCollisionObject());
	newPt.m_combinedRollingFriction = gCalculateCombinedRollingFrictionCallback(m_body0Wrap->getCollisionObject(), m_body1Wrap->getCollisionObject());
	newPt.m_combinedSpinningFriction = gCalculateCombinedSpinningFrictionCallback(m_body0Wrap->getCollisionObject(), m_body1Wrap->getCollisionObject());

	if ((m_body0Wrap->getCollisionObject()->getCollisionFlags() & cbtCollisionObject::CF_HAS_CONTACT_STIFFNESS_DAMPING) ||
		(m_body1Wrap->getCollisionObject()->getCollisionFlags() & cbtCollisionObject::CF_HAS_CONTACT_STIFFNESS_DAMPING))
	{
		newPt.m_combinedContactDamping1 = gCalculateCombinedContactDampingCallback(m_body0Wrap->getCollisionObject(), m_body1Wrap->getCollisionObject());
		newPt.m_combinedContactStiffness1 = gCalculateCombinedContactStiffnessCallback(m_body0Wrap->getCollisionObject(), m_body1Wrap->getCollisionObject());
		newPt.m_contactPointFlags |= BT_CONTACT_FLAG_CONTACT_STIFFNESS_DAMPING;
	}

	if ((m_body0Wrap->getCollisionObject()->getCollisionFlags() & cbtCollisionObject::CF_HAS_FRICTION_ANCHOR) ||
		(m_body1Wrap->getCollisionObject()->getCollisionFlags() & cbtCollisionObject::CF_HAS_FRICTION_ANCHOR))
	{
		newPt.m_contactPointFlags |= BT_CONTACT_FLAG_FRICTION_ANCHOR;
	}

	cbtPlaneSpace1(newPt.m_normalWorldOnB, newPt.m_lateralFrictionDir1, newPt.m_lateralFrictionDir2);

	//BP mod, store contact triangles.
	if (isSwapped)
	{
		newPt.m_partId0 = m_partId1;
		newPt.m_partId1 = m_partId0;
		newPt.m_index0 = m_index1;
		newPt.m_index1 = m_index0;
	}
	else
	{
		newPt.m_partId0 = m_partId0;
		newPt.m_partId1 = m_partId1;
		newPt.m_index0 = m_index0;
		newPt.m_index1 = m_index1;
	}
	//printf("depth=%f\n",depth);
	///@todo, check this for any side effects
	if (insertIndex >= 0)
	{
		//const cbtManifoldPoint& oldPoint = m_manifoldPtr->getContactPoint(insertIndex);
		m_manifoldPtr->replaceContactPoint(newPt, insertIndex);
	}
	else
	{
		insertIndex = m_manifoldPtr->addManifoldPoint(newPt);
	}

	//User can override friction and/or restitution
	if (gContactAddedCallback &&
		//and if either of the two bodies requires custom material
		((m_body0Wrap->getCollisionObject()->getCollisionFlags() & cbtCollisionObject::CF_CUSTOM_MATERIAL_CALLBACK) ||
		 (m_body1Wrap->getCollisionObject()->getCollisionFlags() & cbtCollisionObject::CF_CUSTOM_MATERIAL_CALLBACK)))
	{
		//experimental feature info, for per-triangle material etc.
		const cbtCollisionObjectWrapper* obj0Wrap = isSwapped ? m_body1Wrap : m_body0Wrap;
		const cbtCollisionObjectWrapper* obj1Wrap = isSwapped ? m_body0Wrap : m_body1Wrap;
		(*gContactAddedCallback)(m_manifoldPtr->getContactPoint(insertIndex), obj0Wrap, newPt.m_partId0, newPt.m_index0, obj1Wrap, newPt.m_partId1, newPt.m_index1);
	}

	if (gContactStartedCallback && isNewCollision)
	{
		gContactStartedCallback(m_manifoldPtr);
	}
}
